Avian pneumovirus (APV) is a member of the Paramyxoviridae family of viruses. Pringle, 1996, Arch. Virol., 141:2251-2256. It is the etiological agent of turkey rhinotracheitis (TRT), causing an acute upper respiratory tract infection characterized by coughing, nasal discharge, tracheal rales, foamy conjunctivitis and sinusitis in young poults. In laying birds, there is a transient drop in egg production along with mild respiratory tract illness. Jones, 1996, Avian Pathol., 25:639-648. While uncomplicated cases of APV infection usually result in low mortality, secondary bacterial and/or viral infections can result in Lip to 25% mortality. Id.
APV was first detected in South Africa in 1978, and later detected in the UK, France, Spain, Germany, Italy, Netherlands, Israel, and Asia. See Alexander, 1997, In Diseases of Poultry; 10th Edition, Barnes et al., eds., 541-569; and Jones, supra. The first United States APV case was in Colorado in 1996. See Kleven, 1997, Proc. U.S. Animal Health. Assoc. 101st Annual Mtg., 486-491. Subsequent APV infections were reported in Minnesota and neighboring states. See Lauer, 1999, Minnesota Poultry Testing Laboratory Monthly Report. By 1999, at least 37% of the turkey flocks in Minnesota were positive for APV antibodies, causing economic losses of approximately 15 million dollars per year.
APV virus has been detected in some wild bird species (see, for example, Shin et al., 2000, J. Clin. Micro., 38:4282-4284), and other paramyxoviruses have been isolated from waterfowl (see, for example, Kelleher et al., 1984, Avian Dis., 29:400-407). Experimental studies have shown that Peking ducks (Anas platyrhynchos) are susceptible to infection with APV (Shin et al., 2001, Am. J. Vet. Res., 62:991-994). In addition, the virus has been detected in sentinel Mallard ducks (Anas platyrhynchos) (Shin et al., 2000, J. Clin. Micro., 38:4282-4284). More recent studies have shown that sentinel Mallard ducks living in a pond adjacent to a turkey farm with an APV outbreak acquired the virus and developed anti-APV antibodies (Shin et al., 2002, Virus Res., 83:207-212).